Fast Centrifugal Oil Pump Design and Automated …...Pump Summit 2014, 2 –3 December 2014, DüsseldorfFast Centrifugal Oil Pump Design and Automated Evaluation by 3D-CFD PUMP SUMMIT

Pump Summit 2014, 2 – 3 December 2014, Düsseldorf

Fast Centrifugal Oil Pump Design and

Automated Evaluation by 3D-CFD

Eduard Moser, Ralph-Peter Mueller, Anne Schubert, Dr. Oliver Velde

PUMP SUMMIT 2014, 2 – 3 DECEMBER 2014, DÜSSELDORF

CFturbo® Software & Engineering GmbH

Engineering CAD & Prototyping

• Turbomachinery Conceptual Design

• CFD/FEA Simulation

• Optimization

• 3D-CAD Modeling

• Prototyping

• Testing, Validation

CFturbo® Software

• Turbomachinery Design Software

• Automated Workflows

CFturbo® - The Turbomachinery Design Company


CFturbo® - Input and Output Data

CFturbo®

Fundamental equationsEuler-eq. of Turbomachinery,

Continuity equation, Momentum equation, …

Empirical functionsPublic knowledge,

Proprietory Know-How Existing geometry-elements, imported

Reference geometry –elements, from CFturboDefine operating point

Q, Dp, speed, Fluid propertiesInlet conditions New and / or

modifiedcomponents


Turbomachinery Development Process using CFturbo®

ConceptualDesign

CFturbo®

MeshingANSA, AutoGrid, ICEM, Pointwise, TurboGrid, …

3D-CADAutoCAD, Creo, Inventor,

NX, SolidWorks, …

ProductionRe-computation/optimizationinteractively or automated

CFD/FEA SimulationSTAR CCM+, ANSYS-CFX,FINE/Turbo, PumpLinx, …

ExperimentsPrototyping,

Validation

Design Simulation & Validation Product


CFturbo® - Interfaces to selected 3D-CFD-Codes

CFturbo®

ANSYS ANSYS-CFX

ESI/Open CFD OpenFOAM

NUMECA FINE/Turbo

PumpLinx

STAR CCM+

ICEM, TurboGrid

Snappy Hex Mesh

AutoGrid, HexPress

Simerics

CD-adapco

Seamless interfaces for automated workflows and optimization

Conceptual Design Meshing Simulation


Conceptual Design of the Pump Stage

DESIGN POINT

Volume flow Q 2,75 m³/hPresssure rise DP 1,50 barSpeed n 6.000 rpmFluid Density r20 936 kg/m³


Automated Meshing

Direct Interface in CFturbo

Using PumpLinx® to createcarthesian binary tree mesh

Approx. 2,0 mio. nodes


Steady State (MFR) and Transient Simulation

Hardware: Modern desktop workstation, 8 cores

Computational time - Steady State (MFR) 20 … 30 min. /operating point- Transient 3 hours/operating point- Batch mode runs

Steady State (MFR) Transient


Design & Simulation Process

CAE-engineering process to design and simulate the oil pump, 8 model variations, delivery time less than one week

Design point defintion

Volume flow Q 2,75 m³/hPresssure rise DP 1,50 barSpeed n 6.000 rpmFluid Density r20 936 kg/m³

Modified fluid data for simulation (oil)

Density (20°) r20 936 kg/m³Density (70°) r70 890 kg/m³Viscosity (20°) n20 0.009 Pa sViscosity (70°) n70 0.004 Pa s

8 Designs 8 Performance curves 1 Prototype built


Fluid PropertiesDensity= f (Temperature)

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

-50 0 50 100 150 200

r [

kg/m

³]

T [°C]

Oil (SYLTHERM 800) WATER


Fluid PropertiesDynamic Viscosity = f (Temperature)

0

10

20

30

40

50

60

70

-50 0 50 100 150 200

h[m

Pas

]

T [°C]

Oil (SYLTHERM 800) WATER


0

25000

50000

75000

100000

125000

150000

175000

200000

0 1 2 3 4 5

Dp

tot,

Stag

e[P

a]

Q [m³/h]

Oil T-25 Oil T0 Oil T25 Oil T70 Oil T100 Water T25

Simulation Results – MFR

Pump Performance Curves = f (Volume Flow, Temperature)



Hydraulic Efficiency = f (Volume Flow, Temperature)

0,00

0,10

0,20

0,30

0,40

0,50

0,60

0,70

0 1 2 3 4 5

h[-

]

Q [m³/h]

Oil T-25 Oil T0 Oil T25 Oil T70 Oil T100 Water T25


0,00

0,10

0,20

0,30

0,40

0,50

0,60

0,70

20000

40000

60000

80000

100000

120000

140000

160000

180000

0 0,005 0,01 0,015 0,02 0,025 0,03 0,035 0,04

h[-

]

Dp

tot,

Stag

e[P

a]

Dynamic viscosity h [Pas]

Q=2,75m³/h

Dptot,Stage h [-]


Hydraulic Efficiency, Total Pressure Difference = f (Dynamic Viscosity)

0,00

0,10

0,20

0,30

0,40

0,50

0,60

0,70

20000

40000

60000

80000

100000

120000

140000

160000

180000

-50 0 50 100 150 200 250

h[-

]

Dp

tot,

Stag

e

T [°C]

Q=2,75m³/h

Dptot,Stage h [-]

Hydraulic Efficiency, Total Pressure Difference = f (Oil Temperature)




Static Pressure and Velocity Magnitude @ [T=70°C, Q=2.75 m³/h)

Results – transient flow



0

20000

40000

60000

80000

100000

120000

140000

160000

180000

0 1 2 3 4 5

Dp

tot,

Stag

e[P

a]

Q [m³/h]

T-25T-25 transT0T0 transT25T25 transT70T70 transT100

Performance Map Simulation - Transient vs. Steady State (MFR)



Hydraulic Efficiency Simulation - Transient vs. Steady State (MFR)

0,00

0,10

0,20

0,30

0,40

0,50

0,60

0,70

0 1 2 3 4 5

h[-

]

Q [m³/h]

ÖL

T-25 T-25 trans

T0 T0 trans

T25 T25 trans

T70 T70 trans

T100 T100 trans


Summary - Important Issues for successful design

- Consider all details of pump geometry in early design stage, if possible

- For oil pumps the temperature dependency of fluid properties is importantto perfomance map simulation and efficiency prediction

- Density and viscosity are design relevant and should be used by empiricalcorrelations in early conceptual design phase of a project

- Transient 3D-CFD-simulations should be used for a more accurateperfomance prediction and design decisions, compared to MFR


Summary

The classical design theory of centrifugal pumps uses a large empirical data base for parameters that cannot beeasily described using a pure theoretical approach. This empirical knowledge has been achieved on the basis ofcentrifugal pumps meant to convey water and has been proven to be reliable over the last decades.

On the other hand due to the fact that the automotive sector is under strong pressure to develop more efficient carsthe hybridization of the complete drive concept is proceeding significantly. In this context it is more and moreinteresting to use centrifugal pumps for the transport of oil in the engine or gear box. Here the higher viscosity of oilagainst water is an issue that weakens the so far used set of empirical co-relations in the design process, because itcannot easily transformed into a comprehensive and reliable empirical knowledge basis for the design of centrifugaloil pumps.

It is state of the art that in the design process of centrifugal pumps simulation techniques are widely used prior a realhardware test. This saves a lot of time and money as the first prototype is very close to a hydraulically good machine.By trend the design of centrifugal oil pumps is a more lengthy process compared to that of water pumps as theempirical data base is weaker and more design cycles are necessary. Therefore a highly automated and robustworkflow is desired that comprehends both the CAD-design of the pump as well as the test of the current designusing modern simulation techniques.

In this paper a method has been presented that uses empirical correlations to adapt water pump design rules to oilpumps and establishes and fully automated CFD workflow for virtual testing. It allows an almost immediate responsefrom the simulation environment once the design of the hydraulic components has been finished. Using thisapproach design and test are not any longer separate processes but are seamlessly connected. One gets a straightanswer on every design parameter change and can go through the design process very intuitively and is herewith notreliant on an accurate empirical data basis. In future more and more correlations can be computed for oil and otherfluids by the use of cloud computing. New knowledge will become available for conceptual design of oil pumps too.

Documents

Fast Centrifugal Oil Pump Design and Automated …...Pump Summit 2014, 2 –3 December 2014, DüsseldorfFast Centrifugal Oil Pump Design and Automated Evaluation by 3D-CFD PUMP SUMMIT